NATURAL DECEMBER 1999 • USDA FOREST SERVICE

INQUIRER

The Decline 

of the 

Quaking

Aspen

Page 4

The Decline 

of the 

Quaking

Aspen

Page 4

Finding Ways 

to Soak Up 

The Rays

Finding Ways 

to Soak Up 

The Rays

Page 18

Are We 

Having 

FUNGI 

Yet? Page 10

Page 22

There Goes the 

Neighborhood!

Slip Slidin’ Away

Quit 

Horsin’ 

Around!

Page 14

Go

with the

Flow

Page 30

Page 26
The Natural Inquirer

Volume 2, No. 1, Fall, 1999

The Rocky Mountain

Ecoregion

Barbara McDonald

Forest Service Research

Forest Service Scientists:

Dale Bartos, Logan, UT

David Cole, Missoula, MT

Ken Cordell, Athens, GA

Debbie Dumroese, 

Moscow, ID

Christina Hargis, 

Flagstaff, AZ

Sandra Ryan, 

Laramie, WY

Anna Schoettle, Laramie, WY

Editorial Review Board:

Penny Stone’s 6th Grade

Class, Bennion Elementary

School, Salt Lake City, UT

Caprielle Barlow

Robyn Brooks

Chris DelPorto

Ben Fogelson

Lisa Folau

Lillian Geurts

Daniel Hu

Raff Janove

Trent Lowe

Al Lund

Ian Nelson

Katherine Ogilvie

Bo Peng

Damon Peterson

Spencer Pinegar

Balery Pozo

Conor Provenzano

Brendan Schluter

Elisia Schrauth

Privank Sharma

Dallas Shi

Greg Thatcher

Mitch Towner

Ella White

Yan Yuan

Produced by:

Forest Service Research,

Washington, DC

Forest Service 

Conservation Education,

Washington, DC

With Thanks To:

USDA Forest Service, Rocky

Mountain Research Station,

Fort Collins, CO

Forest Service 2002 Planning

Team, Salt Lake City, UT

USDA Forest Service

NatureWatch Program

Penny Stone, 

Bennion Elementary

School, Salt Lake City, UT

Wilson Gonzalez-Espada,

University of Georgia,

Athens, GA

George Avalos, USDA Design

Center, Washington, DC

Deron Davis, 

Dunwoody Nature Center,

Dunwoody, GA

The College of Education,

University of Georgia,

Athens, GA

Penny Stone (top right) and

our Editorial Review Board
Contents

Teacher’s Note . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

About The Natural Inquirer . . . . . . . . . . . . . . . . . . . . 3

What are Scientists? . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Features

Quaking in Their Roots: 

The Decline of Quaking Aspen . . . . . . . . . . . . . . . . . .4

Are We Having Fungi Yet? 

Helping Young Trees Grow . . . . . . . . . . . . . . . . . . . .10

Quit Yer Horsin’ Around! 

The Effects of Trampling 

on Vegetation in Montana . . . . . . . . . . . . . . . . . . . .14

Finding Ways to Soak Up the Rays

Lodgepole Pine Adaptation to 

Different Environmental Conditions . . . . . . . . . . . .18

There Goes the Neighborhood: 

The Disruption of 

American Marten Habitat . . . . . . . . . . . . . . . . . . . . .22

Slip Sliding Away: Who Goes Skiing 

and Snowboarding in America? . . . . . . . . . . . . . . . .26

Go With the Flow: 

Are Mountain Stream Channels 

Shaped by Flood and Drought? . . . . . . . . . . . . . . . .30

Evaluation Forms . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

National Science Education Standards . . . . . . . . . . .37

What is the Forest Service? . . . . . . . . . . . . .Back Cover

The Natural Inquirer is reproduced on recycled paper with soy-based inks.

Please pass this journal along or recycle it when you have finished using it!

1

Page 4

Page 18

Page 26
Teacher’s

Note

Although students should

learn about natural resources

by reading these articles, one

of the main purposes of the

journal is to introduce the

work of scientists to middle

school science students. Our

goal is to stimulate an interest

in natural resource science by

presenting research activities

of a variety of scientists. First,

you and your students will

“Meet the Scientist.” 

In the articles themselves,

“Reflection Questions” are

oriented toward helping you

conduct a class discussion

about the problems, methods,

findings, and implications

associated with each research

article. These questions

should stimulate critical

thinking about the article. 

Critical thinking and discussion may be encouraged

by using small groups,

although entire class discussions may also be helpful.

Note that the answers to the

reflection questions should

not be considered right or

wrong. They are intended to

stimulate critical thinking

only.

The articles, as well as the

journal’s overall format, are

designed to imitate the format

of a professional research

journal. We have, however,

added a number of additional

sections to serve as resources.

• First, the students will read

the section called

“Thinking About Science.”

This section highlights

some aspect of the process

of science that may be

found in the article. The

section called “Thinking

About the Environment”

highlights some aspect of

the content of the article. A

glossary is also included to

help students understand

the more challenging words

in the article. The first

occurrence of these words

in the article is given in bold

print. Understanding these

words will be crucial to the

students’ comprehension of

the article.

• Each article also contains a

“Discovery FACTivity,”

which is a hands-on

inquiry-based activity

intended to illustrate some

aspect of the article.

• In the back of the journal,

you will find a matrix

which will allow you to

identify articles by the

national standards that they

address. National standards

were identified from Project

2061, developed by the

American Association for

the Advancement of

Science.

• Also in the back of the journal, you will find evaluation

forms. After you have read

an article with your class,

please photocopy the

forms, complete them, and

send them to the address

listed.

This journal was created by

the Urban Tree House, an

education program of the

USDA Forest Service. If you

have any questions or comments, please contact:

Dr. Barbara McDonald

Social Scientist

USDA Forest Service

320 Green Street

Athens, GA 30602-2044

706-559-4224

barmac@bigfoot.com

2
Scientists are people 

who collect and evaluate

information about 

a wide range of topics. 

To be a successful natural

resource scientist, 

you must:

• Be curious

You must be interested 

in learning.

• Be enthusiastic

You must be interested 

in a particular topic.

• Be careful

You must be accurate 

in everything you do.

• Be open-minded

You must be willing 

to listen to new ideas.

• Question everything

You must think 

about what you read.

• Care about the 

environment

You must have an 

interest in and respect 

for the natural world.

3

What Are Scientists?

Scientists in this issue

at work.

The Natural Inquirer

Scientists report their research in journals,

which are special booklets that enable

scientists to share information with one

another. This journal, The Natural Inquirer,

was created so that scientists can share their

research with you and with other middle

school students. Each article tells you about

scientific research conducted by scientists in

the USDA Forest Service. If you want to know

more about the Forest Service, you can read

about it on the back cover of this journal.

All of the research in this journal is concerned with nature, such as trees, forests,

wildlife, insects, outdoor activities, and

water. First, you will “meet the scientist”

who conducted the research. Then, you 

will read something special about science,

and then about the environment. You will

also read about a specific research project,

written in the way that scientists write 

when they publish their research in journals. 

You will become a scientist when you do 

the Discovery FACTivity associated with

each article. Don’t forget to learn the 

vocabulary words! They will help you to

understand the article.

At the end of each section of the article,

you will find a few questions to help you

think about the research. These questions are

not a test! They are intended to help you

think more about the research. Your teacher

may use these questions in a class discussion.

Meet Dr. Dale Bartos:

“I like being a scientist

because I enjoy working with

natural systems and attempting to understand how they

function. I am able to communicate this information to

the land managers who (it is

hoped) will do a better job of

caring for the land.” 

Thinking About

Science...

Sometimes, a

scientific question cannot be

answered by

direct observation, such as by

an experiment or by simply

observing what is going on. In

these cases, scientists collect

information from a variety of

sources, then put the pieces

together as if they were gathering and evaluating clues to 

a mystery. In this study, the 

scientists wanted to know

why populations of quaking

aspens are declining in the

Western United States.

Because it would take years 

to watch the growth and

development of an aspen

stand, the scientists tried to

find clues from other sources

to help them understand the

aspen’s decline.

Thinking 

About the

Environment...

Pando—

which means 

“I spread” in

Latin—is the perfect name for

a stand of quaking aspen,

nominated a few years ago as

Earth’s most massive living

individual. The title still

stands, as far as scientists

have determined. In the

Wasatch Mountains of Utah

(on the Fishlake National

Forest — see Figure 1), Pando

Glossary:

biodiversity: 

(bî'ô di vûr'si tê)

various kinds of life

conifer: (kô'ne fer) 

cone-bearing evergreen 

tree or shrub

distribution:

(dis’ tre byôô'shen) the 

frequency of occurrence 

or places where a natural

resource can be found

ecosystem: (ek'ô sis tem)

a system formed by the

interaction of organisms

with their environment

forage: (fôr'ij) plant 

food eaten by wildlife, 

horses, or cattle

forest manager: (fôr'ist

man’i jer) a person who

takes specific actions to 

protect and to use natural

resources in a forest

forest stand: (fôr'ist stand) 

a particular species of tree

growing in a given area

natural history: (nach'er el

his' te rê) history of changes

in the natural environment

over time

stability: (ste bil'i tê) being

likely to continue 

succession: (sek sesh'en) 

the natural replacement,

over time, of one type of

plant life after another 

suppress: (se pres') 

to put an end to; 

to subdue or conquer

Dr. Bartos counts tree rings

with the help of a technician.

Quaking in Their Roots: 

The Decline 

of Quaking

Aspen 

5
weighs about 13 million

pounds. He has upwards of

47,000 stems. That’s 47,000

of what you and I might mistakenly perceive as separate

aspen trees.

Pando is a male aspen.

Unlike several other tree

species, individual aspen are

either male or female.

Quaking aspens like Pando

are able to cover so much

ground by an asexual reproductive process—known as

suckering—involving tree

roots. New stems rise out of

the ground from the aspen’s

network of horizontally

spreading roots. On the surface, these appear to be separate trees, but they are really

part of one individual! (This

information is from Earth

and Sky, Monday, December

9, 1996. Visit their web site at

www.earthsky.com.)

Introduction

The quaking aspen is a tree

that helps us a lot! Aspen use

less water than conifers, provide forage for wildlife, and

support a wide variety of

other kinds of life. The quaking aspen thus helps to maintain the biodiversity of an

area. Aspen are unique,

because they reproduce by

sending small shoots up from

their root systems. This kind

of reproduction is called suckering. In some ways, this is a

disadvantage to them. If they

are lost to an area, they will

not reproduce from seeds like

other trees.

In recent years, populations

of quaking aspen have been in

decline in the Western United

States. Stands of aspen are

now mixed with conifer trees.

Each year, fewer aspen-dominated stands exist in Utah and

other parts of the Western

United States. To be classified

as an aspen stand, the stand

must be more than 50 percent

aspen.

The scientists in this study

wanted to know more about

the decline of quaking aspen.

They also wanted to know

what should be done about

reversing aspen decline, 

so that large aspen stands 

6

Figure 1. Aspen stand in the Fishlake National Forest, Utah.
are not lost in the Western 

United States.

Reflection

• If aspen

declines, what

environmental

benefits will

decline also?

Methods

The scientists collected

information from a wide 

variety of sources. First, they

researched the natural history

of the area. They specifically

looked at the history of fire

and of the distribution of

aspen. In part, they learned

about the fire history from

two ponderosa pine trees

(Figure 2). Even though ponderosa pine trees can’t talk,

they can still tell scientists

about past fires. The scientists

took a small slice from the

trunk of each of the pine trees

and examined the slice for fire

scars near the trees’ growth

rings (Figure 3).

The scientists also dug

trenches in forest stands of

pure aspen, and in stands

with a mixture of aspen and

conifer trees (Figure 4). They

pulled the aspen roots from

these trenches and counted

them. In this way, they could

determine whether aspen

reproduction was declining 

in stands being shared with

conifers. 

Figure 2. Ponderosa pine damaged by fire.

Figure 3. Fire-scarred growth rings from ponderosa pine.

7
Reflection

• What is it

about the number of aspen

roots that

would tell the

scientists that aspen reproduction is declining in

mixed stands, as compared

with stands with mostly

aspen trees? 

• What is the relationship

between fire and the growth

of conifer trees in aspen

stands?

Results

By looking at the trunk

slices, the scientists discovered

that nine fires had occurred

during the early lifetime of the

Ponderosa pines, but that no

fires had occurred since 1836.

Prior to 1836, fires burned in

this area about every 19

years. These fires were helpful

to aspens because they

reduced the competition of

other species. Aspens regrew

after the fires had burned,

and, therefore, these small

fires actually helped the aspen

stands to remain healthy. Fire

acted like a feedback mechanism that helped to keep the

aspen ecosystem balanced

within certain limits. 

Over the past 150 years,

humans have suppressed fires,

and have allowed livestock to

graze among the aspen. These

activities have allowed forest

succession to proceed. When

this happens in aspen stands,

the aspens begin to die and

the areas become dominated

by conifers and/or sagebrush.

This is what is happening

now to the aspen stands studied by Dr. Bartos and Mr.

Campbell.

Reflection

• If fires are not

allowed to

burn, the aspen

in an ecosystem

are gradually

replaced by other trees.

How does fire maintain the

stability of the aspen

ecosystem?

Implications

Unless forest managers

make some changes, the 

population of aspen trees in

the Western United States 

will continue to decline.

Recommended changes

include reducing livestock

grazing among aspen trees

and beginning a program to

allow fires to burn about

every 20 years within aspen

stands. 

The scientists know a great

deal about how to save the

quaking aspen, but more

research is needed. What they

do know is that if the aspen

population continues to

decline, many of the environmental benefits of aspen

ecosystems will also decline.

Reflection

• If you were

the scientist,

what would you

suggest should

be done about

the decline of

quaking aspen?

From: Bartos, Dale L. and Campbell, Jr.,

Robert B. (1998). Decline of Quaking

Aspen in the Interior West— Examples

from Utah, Rangelands, 20(1): 17–24.

8

Figure 4. Digging up the aspen roots and counting them.
Discovery

FACTivity

When a tree is

cut down or a

branch is cut off

of a tree, the

trunk or branch shows a pattern of rings. Each ring is a

layer of wood produced during 1 year’s growing season.

Have your teacher bring thin

slices from a cut tree or

branch, enough for each student or for small teams of students. Carefully examine the

rings. In years with good

growing conditions, the area

between rings is large, indicating a lot of growth. In

years of drought, insect damage, fire, root damage, or

other stress, the area between

rings is small and may actually show the damage, indicating poor growth in that year.

See the example.

What can you determine

about the tree’s (or branch’s)

life and the yearly environmental conditions by reading

tree rings? See if you can even

count the rings to determine

the tree’s (or branch’s) age. 

Just like trees, people grow

each year. We are going to

borrow the idea of reading

tree rings, except that you are

going to draw your own life

story, just as if you were a

tree. Get a plain piece of

paper. Put a dot in the center.

The dot represents the year

you were born. Now, draw

circles around the dot. Each

circle represents a year of

your life. If you grew a lot 

1 year, leave a lot of area in

between that circle and the

next larger one. You can show

memorable events in your life

on the rings. Share your life

stories with other students in

the class. See the example

below.

For more information, see:

www.xmission.com/~rmrs/

staffs/labs/logan/logan_int43

01.html

9
Meet Dr. Debbie Dumroese:

“I like being a scientist

because I love learning about

how different soils grow

unique forest plants and

fungi, and I like working on

ways to continue harvesting

timber without damaging the

soil. The other reasons I like

science are the opportunity to

work with some especially

gifted people, and to continue

learning about the world.”

Thinking About

Science...

Scientists

often use math

to help them do

their work. Can

you guess why?

When scientists do experiments or conduct research,

they often measure the

amount of something. Then,

they compare the measurements to look for similarities

or differences. Scientists also

use numbers and words to

present their results to other

scientists. You can see that

math and science are closely

related. Can you guess what

other subject is necessary to

scientists? Think about The

Natural Inquirer. Besides

understanding numbers, what

else do you need to do to

learn about science? What are

you doing right now?

Thinking 

About the

Environment...

Scientists have

discovered that

certain fungi

grow on the roots of plants, to

the benefit of both the fungi

and the plant. The fruiting

bodies of fungi are mushrooms, but most of the organism lives underground. This

mutually beneficial relationship between plants and fungi

is called mycorrhiza (my koe

rye’ zuh). The fungi absorbs

nutrients from the soil and

provides them to the plant,

and the plant provides 

nutrients to the fungi.

Everybody wins! This is like

many relationships in nature,

where different kinds of

10

Are We 

Having 

FUNGI 

Yet?

Helping Young 

Trees to Grow

Dr. Debbie Dumroese Figure 1. Ectomycorrhiza

fungi growing on tree roots.
the non-native fungi that

might be growing on the

seedlings’ roots. The scientists hypothesized that if the

new seedlings were cleared of

nonnative fungi before being

planted, the native ectomycorrhiza fungi would spread

from nearby forested areas

and grow on the young

seedlings’ roots. This would

help the seedlings to get

nutrients, to grow faster and

stronger.

Reflection

• What 

problem are 

the scientists

trying to solve?

• If foresters do not plant

seedlings on the harvested

areas, what do you think

will happen to the areas?

Why do foresters want to

plant seedlings in harvested

areas?

• Why do you think native

ectomycorrhiza fungi are

better for the seedlings 

than nonnative fungi?

Methods

The scientists applied one

kind of chemical to the soil

before planting the seedlings.

This procedure is called 

fumigation and involves

pouring a liquid chemical

onto the ground, then covering the ground with plastic

(Figures 2 and 3). The plastic

keeps the chemical from

escaping into the air. Why do

you think that it is important

to cover the ground with plasGlossary:

fumigation: 

(fyôo'me gâ'shen) a

method used to kill weeds,

insects, and disease

organisms in soil, usually

with a liquid or a gas

fungicide: (fun'ji sîd') 

a chemical used to destroy

fungi

harvest: (här'vist) 

to gather or take a crop 

hypothesize: (hî poth'i

sîz’) to propose an

explanation in light of

known facts

mutually beneficial:

(myôô'chôô el'lê ben'e

fish'el) each having and

gaining advantage from

the other or others

native: (nâ'tiv) 

living or growing

naturally in a particular

region

nursery: (nûr'se rê)

a place where young trees

or plants are grown

nutrient: (nôô'trê ent)

something containing

food

seedling: (sêd'ling)

a young plant grown 

from a seed

timber: (tim'bêr)

trees or their wood

11

organisms work together so

that they all remain healthy.

This relationship works best

when the organisms are all

native to the area in which

they are growing. The scientists in this study were interested in the fungi that grow on

the outside of tree roots

(Figure 1). They call this ecto-

(meaning outer) mycorrhiza

fungi.

Introduction

In the Western United

States, shallow, rocky soils

and a dry climate often make

it hard for new trees to grow

on areas that have been harvested of older trees. Sometimes, areas that have been

harvested grow back quickly

in other types of plants. These

plants compete with young

trees for moisture and nutrients. This makes it hard for

new trees to grow. Often

before planting seedlings,

foresters will clear an area of

competing plants by setting

fires and burning the plants.

This does not always work

well because the plants grow

back quickly and again compete with the seedlings. 

The scientists in this study

wanted to test a different

way of reducing the competition for soil nutrients and

moisture. They did this by

applying two different types

of chemicals. One chemical

was applied directly to the

soil to kill the plants. The

other chemical was applied

directly to the seedlings,

before the seedlings were

planted. This was done to kill
tic? (Hint: Think about your

health, and also about the 

loss of chemicals from the

ground.) The plastic was

removed from the ground 

2 weeks before planting the

seedlings.

The scientists also applied 

a fungicide directly to some 

of the seedlings in the nursery

before planting them outside.

The fungicide was applied to

kill the fungi that grow on the

seedlings’ roots in the nursery.

Some of these seedlings were

planted in areas that had not

been fumigated. That way, the

scientists could find out

whether fumigation affects

the seedlings’ growth. They

could also find out if the

application of a fungicide

affects the seedlings’ growth.

The scientists measured the

growth of the seedlings every

year for 2 years. They measured the seedlings’ height,

analyzed their nutrient content, and counted the number

of seedling roots that had

ectomycorrhiza fungi growing

on them. (The scientists

expected the native ectomycorrhiza fungi to begin growing on the roots, even though

the roots had been exposed to

fungicide.) In this way, they

used numbers to compare the

use of fungicide alone on

seedling and ectomycorrhiza

growth. They compared this

with the use of fungicide and

soil fumigation together on

seedling and ectomycorrihiza

growth.

12

Figure 2. Pouring liquid onto the ground.

Figure 3. Covering the ground with plastic.
Reflection

• Why did the

scientists plant

some seedlings

in areas that

had not been

fumigated?

• Do you think the ectomycorrhiza fungi were able to

begin growing on the 

seedlings’ roots? Why 

or why not?

Results

The scientists found that

when they fumigated the soil

in the spring, the seedlings

grew more than when they

fumigated in the fall. They

also discovered that the

seedlings not treated with

fungicide grew larger than

those that had been treated

with fungicide.

They found that the use of

the fungicide resulted in a

greater amount of ectomycorrhiza fungi growing on the

seedlings’ roots by the second

year. When you think about

all of these findings, you will

see that the presence of more

ectomycorrihiza fungi does

not always mean that

seedlings will grow larger,

even though the fungi are 

providing nutrients to the

seedlings. 

Reflection

• If you want

to grow the

biggest

seedlings,

which treatment would you use?

Would you use just the

fumigation, just the fungicide, or both?

• Do you think the scientists

were surprised to find that

ectomycorrhiza fungi did not

make the seedlings grow

larger? Why or why not? 

Implications

If foresters want their

seedlings to grow successfully

and quickly, they should

fumigate the soil in the spring

before they plant the seedlings. Unfortunately, soil

fumigation is expensive. The

scientists therefore recommend that fumigation only be

used on areas where seedlings

have a lot of competition

from other plants.

Reflection

• What are

some of the

advantages and

disadvantages

of soil 

fumigation?

• This study pointed out

examples of competition

and cooperation in natural

systems. Where was the

competition? Where was

the cooperation? What are

other examples of competition and cooperation in

nature?

• Even though the native

ectomycorrhiza fungi did

not help the seedlings grow

larger, do you think the

native ectomycorrhiza fungi

are beneficial to the

seedling? Why or why not?

From: Page-Dumroese, Alan E. Harvey,

Martin F. Jurgensen, and Michael J.

Larsen (1996). Ponderosa pine seedling

response to planting-site soil fumigation

and fungicide application, Northwest

Science, 70(2), 139–147.

Discovery

FACTivity

Bring in a

small bag of

sterilized potting soil, and

similar amounts

of soil from the woods, a garden, and from an area with a

lot of weeds or other types of

plants. Think about the sterilized potting soil. What does

sterilized mean? Why would

people want to buy sterilized

potting soil? Compare the

sterilized potting soil with the

other soil. Besides the color,

what are the differences? Can

you find any animal or plant

life in the sterilized soil? How

might that be an advantage or

disadvantage to house plants?

Further Discovery

Plant a house plant using

the sterilized potting soil, and

one in each of the other soils.

Treat them all the same. Over

a period of months, observe

what happens in each of the

pots. Is there a difference

between the pot with the sterilized soil and the other pots?

What is the difference? Why

is there a difference?

For more information, see:

http://forest.moscowfsl.wsu

.edu/

13
Meet Dr. David Cole:

“I like being a scientist

because I get to exercise my

curiosity and discover things

that might help make the

world a better place.”

Thinking About

Science...

Scientists

often set up

experimental

conditions to

study a particular problem. If scientists control what happens during an

experiment, they feel more

certain about the results.

Often, scientists will compare

what happens under different

conditions. When they work

in a laboratory, it is easier to

control conditions. Sometimes, however, scientists cannot do their experiments in a

laboratory. The scientists in

this study wanted to find out

whether horses or llamas do

more damage to Rocky

Mountain vegetation. Do you

think they did this study in a

laboratory?

Thinking 

About the

Environment...

Whenever

people use 

natural

resources, they have an

impact on them. The scientists in this study were concerned about the impact of

large domestic pack animals

used to carry equipment in

the back country. Large animals may have more of an

impact on vegetation than

smaller animals and humans.

This is of special concern in

mountain environments,

which are more fragile for

vegetation. The scientists

studied the difference in

impacts between horses and

llamas. Llamas are a South

American member of the

camel family. Llamas are

about 4 feet high and 4 feet

long (plus a short tail!). They

were used as pack animals at

least 4,000 years ago by the

Indians of Peru.

Introduction

When people go hiking or

camping in back country or

wilderness areas, they almost

always impact the natural

environment in some way. For

example, hiking along trails

wears down the soil and causQuit Yer Horsin’

Around!

The Effects of Trampling

on Vegetation in Montana

Dr. David Cole

14
Method

The scientists found places

to study in the back country.

To study the effects of trampling on the vegetation, four

sets of lanes were created. A

lane was created by marking a

long and skinny area, like a

path. The lanes went right

through the vegetation (like

the first time anybody uses a

short cut!). One set of lanes

was used as a control. The

control, which was left

untrampled, was used to compare what happened in the

trampled lanes with an

untrampled lane. 

That left three sets of lanes

for the treatments. One of the

3 sets of lanes was trampled

by a human walking down the

lane 150 times, another was

trampled by a llama —being

led by a human— walking

down the lane 150 times, and

the third was trampled by a

horse—being led by a

human—walking down the

third lane 150 times (Figures

1 and 2).

The scientists measured the

forbs (or small herb-like

plants) and shrubs before and

within 2 weeks after trampling

in each of the lanes. They measured vegetative cover and

height. Then, they calculated

the average amount of cover

and the average height of the

forbs and shrubs in each of the

lanes. The scientists then used

a statistical test to determine

whether the measured differences in vegetative cover and

height were probably due to

something other than normal

vegetative differences.

Glossary:

back country: (bak kun'trê)

a large natural area with

little or no human

development

control: (ken trôl) situation

in which the experimental

treatment is withheld, used

as a comparison 

domestic: (de mes'tik)

raised to live in a tame

condition

erosion: (i rô'zhen)

the state of being destroyed

by wearing away

experimental condition:

(ik sper'e men'tel 

ken dish' en) a situation

purposely created to run 

a test or trial

forest manager: (for'ist 

man'i jer) a person who

takes specific actions to

protect and to use natural

resources in a forest

fragile: (fraj'el) easily

damaged

natural resource:

(nach'er el rê'sôrs) goods

occurring in nature that are

used by humans

statistical test: (ste tis'ti kel

test) a test that uses numbers

and probability to determine

relationship

trampling: (tramp'ling)

treading or stepping heavily

treatment: (trêt'ment)

a purposeful action taken to

test something or run a trial

vegetation: (vej'i tâ'shen)

all the plants or plant life 

in a place

vegetative cover:

(vej'i tâ'tiv kuv'er) 

layer of green vegetation

15

es erosion. A look at the trails

around your school yard or in

your local park will show you

what happens when there is a

lot of trail use. When people

use the back country, they

sometimes use pack animals

to make their trip easier. In

the past, people used horses,

mules, and donkeys to carry

their load. More recently,

people have also begun using

llamas to help them carry

their hiking and camping

gear.

While much trampling

occurs on trails, for pack animals, it can also occur where

the animals are grazing.

Scientists know very little

about the environmental

impacts of pack animals on

vegetation. But since so many

people are using horses and

llamas when they visit the

back country, it is important

to understand what happens

to vegetation that is being

used by these people and

their animals. That’s why Dr.

Cole and Dr. Spildie studied

what happens to vegetation

that is being trampled by people, horses, and llamas.

Reflection

• What 

problem are 

the scientists

trying to solve?

• If you were the scientist,

how would you find out

about the effects of trampling by horses, llamas, and

people?
Reflection

• What were

the scientists

trying to measure?

• Why do you think the scientists used a control?

• What do you think the scientists discovered about the

effects of trampling on vegetation? Why?

Results

The amount of vegetative

cover was so much lower for

the lanes trampled by the

horse, the scientists knew it

had to be due to the horse

(Figure 3). However, the scientists found no statistical difference in the height of the

vegetation. This means that

even though the average

heights were different for the

vegetation in each of the

treatments, they were not different enough to know for

sure whether the horse or

llama caused any more damage to the height of the plants

than the human.

In general, the horse caused

a lot more damage to the

vegetation than either the

llama or the human. The

scientists were surprised to

find that llamas did not cause

more damage to the vegetation than humans. Are you

surprised? 

Reflection

• Do you think

the results are

accurate? Do

you believe that

llamas do not

create any more damage to

vegetation than humans?

Why or why not?

• If you were a forest manager, what would you do to

protect vegetation from too

much damage?

Implications

If forest managers want to

minimize the impact of 

visitors to the back country

environment, they need to be

aware that horses are more

damaging to vegetation than

llamas or people. Managers

may want to limit the use of

horses for packing gear, and

encourage the use of llamas

instead.

Reflection

• When people

use the back

country for 

hiking and

camping, even

if they don’t use horses,

they have an impact on the

environment. Do you think

100

90

80

70

60

50

40

30

20

10

0

Llama Human Horse

Shrubs

Llama Human Horse

Forbs

Percent Vegetative Cover

Figure 3. Bar chart of the results of the experiment.

Figure 1. Leading the llama

down the test path.

Figure 2. Leading the horse

down the test path

16
people should be allowed to

go in to the back country?

Why or why not?

From: Cole, D. N. and Spildie, D. R.

(1998). Hiker, horse and llama trampling

effects on native vegetation in Montana,

USA. Journal of Environmental

Management, 53, 61–71.

Discovery

FACTivity

The scientists

in this study

wanted to

know whether

trampling has an impact on

plants. We’re going to try the

same experiment, but instead

of using horses and llamas,

we’ll use aluminum cans 

and a plastic bottle. And

instead of trampling, we’ll 

be pounding! 

Line four shoe boxes with

plastic. Dig up four small rectangles of weeds, small

enough to fit in the shoe

boxes. Make sure to dig up

some of the soil as well. The

four weed samples should be

as similar as possible, so dig

them from the same area.

Place one sample in each shoe

box. Number each of the

boxes. Using a ruler, measure

the height of the weeds at

each corner and in four places

in the middle. 

Calculate the average

height of the weeds in each

shoe box. Make a record of

the average height of each

sample. 

Compare the average

heights of the weeds in all 

four boxes. They should be

very similar. If they are not,

you will need to dig samples

again until you get four samples with very similar average

heights.

Get a plastic bottle filled

with water, and two empty

aluminum cans. Fill one can

with sand or small rocks and

tape the hole shut. Leave the

other can empty. 

Box number 1 will be your

control. You will use it for

comparison, so you will not

do anything to the weeds in it.

Have your class form three

teams, choosing three members from each team to pound

the weeds. Assign one of the

remaining boxes and the plastic bottle or one of the aluminum cans to each team.

Have the 3 members of each

team pound the weeds 50

times (for a total of 150

times) with the bottle or can.

Make sure all areas of the box

are pounded.

After the weeds have been

pounded 150 times, measure

their height once again.

Measure in each corner, and

in four places in the middle.

Calculate an average of the

height of the weeds in each

box, and record it. Compare

the average heights of the

weeds in all four boxes.

Which box contains the lowest weeds? Which contains

the highest? Why do you

think there are differences

between the heights of the

weeds? What is the purpose

of the control box? 

Using the average heights

you calculated for each box,

create a bar chart showing

your results using the empty

chart below.

For more information, see:

http://absaroka.wilderness.

umt.edu/leopold

10

9

8

7

6

5

4

3

2

1

0

Before After

Empty Can

Before After

Plastic Bottle

Before After

Full Can

Average Height in Inches

17
Meet Dr. Anna Schoettle

(pronounced “shuttle”):

“I like being a scientist

because it is fun to ask questions, solve problems, and

discover new information

about plants and ecosystems.”

Thinking About

Science...

Scientists

work in a variety of settings,

and are

employed by

different organizations.

Scientists work for universities,

business and industry, hospitals, and the government.

Scientists work in many different settings, such as laboratories, classrooms, factories,

oceans, forests, in space, or on

farms. The scientist in this

study works for the USDA

Forest Service, a Government

agency that manages many of

our Nation’s forests. She collected branches from pine trees

in the Rocky Mountain forests

of Colorado. Then, she took

the branches into a laboratory,

took measurements of the

branches and pine needles, and

used a computer to compare

her results. You can see that

scientists work in a lot of different settings. What setting

would you like to work in?

Thinking 

About the

Environment...

Organisms

must be able to

live in a constantly changing environment. (Think about yourself.

Don’t you need to do that

too?) If an organism is to survive, it will try to keep its

internal environment stable,

regardless of the external

environment. This means that

organisms will try to adapt

over time to survive in changing environments. The scientist in this study wanted to

know why lodgepole pines

can survive at very different

elevations in the Colorado

Rocky Mountains. This

shows that the pines can live

in very different environ18

Finding Ways to

Soak Up the Rays

Lodgepole Pine Adaptation to

Different Environmental Conditions

Dr. Anna Schoettle
Reflection

• Why might it

be important

for plants to be

able to adjust to

different environments? (Hint—Can a

plant move from place to

place?)

• How does one test 

a hypothesis?

Methods

When scientists study things,

they usually study more than

one example of it. The scientist

therefore selected six forested

areas at two elevations (three

sites at each elevation). Four

trees in each of the six areas

were selected for study. (How

many trees did the scientist

study?) Then, the scientist

selected an area in the lower

third of each of the trees’

crown from which she cut

shoots. Dr. Schoettle measured

four things: 1) the length of the

shoot that had attached needles, 2) the age of the oldest

pine needle on the shoot, 3)

how much the shoot had

grown each year, and 4) the

total biomass of the needles on

the shoot (Figure 1). Biomass is

measured by weight. The

weight of the needles was measured by drying them in an

oven and weighing them.

Dr. Schoettle then compared

the four measurements using a

computer program. The computer program helped her to

determine if there were differences between the measurements of the shoots on trees

growing at different elevations. 

Glossary:

adapt: (edapt')

to adjust to new 

conditions

biomass: (bî'o mas)

that part of a habitat

consisting of living 

matter

crown: (kroun')

the leaves and living

branches of a tree

data: (dât'e)

information

elevation: (el'e vâ'tion)

the height above sea 

level

foliage: (fôl'ê ij)

leaves of a plant or 

all plants

hypothesize: 

(hî poth'e sîz) to propose 

an explanation in light 

of known facts

photosynthesis:

(fôtô sin'the sis) the 

process that plants use, 

with the aid of sunlight, 

to create food in the 

form of carbohydrates 

19

ments. The scientist was interested in discovering how

lodgepole pines adapt to living in such different environments.

Introduction

Sunlight is the source of

energy for plants, which 

create food through photosynthesis. Photosynthesis

occurs in the foliage, or green

leaves (or needles) of a plant.

The amount of food a plant

can produce is partly dependent on the amount of its leaf

or needle surface area.

Lodgepole pines grow in

mountain forests at very different elevations. Dr.

Schoettle, the scientist in this

study, hypothesized that pines

growing at higher elevations

adapt to these harsher environmental conditions by

growing needles that live for

more years than needles

growing at lower elevations.

She also hypothesized that the

shoots (branches) of higherelevation pines would grow

less each year than the shoots

of pines growing in the lower

elevations. The interaction of

growing less and the longer

lifespan of the needles should

equal out across elevations,

maintaining the same

amount of green needle area

available for photosynthesis

by the pines. Dr. Schoettle

hypothesized that lodgepole

pines have adapted in this

way to live at different elevations. She wanted to test this

hypothesis.
Reflection

• Why do 

you think 

scientists usually study more

than one example of something? Do you

think Dr. Schoettle should

have studied only one tree

at each elevation, rather

than 12? Why or why not?

• Why did Dr. Schoettle want

to know the total weight of

the needles? (Hint—Weight

is a measure of the amount

of something, and Dr.

Schoettle wanted to know

the amount of green needle

area available for photosynthesis.)

Results

The results of the study are

presented in Table 1. The needles growing on pines at higher elevations lived longer than

the needles growing on pines

at lower elevations. The

shoots of these higher elevation pines, however, did not

grow as much each year as the

branches at lower elevations.

The length and weight of the

needles on all shoots were

about the same, meaning that

the same amount of green

area was available for photosynthesis, regardless of where

the trees grew.

Reflection

• What 

conclusion

would you

draw from

these results

about the adaptation of

lodgepole pine at higher 

elevations?

• Was Dr. Schoettle’s hypothesis proved true or false

by this study? How do you

know whether it was true

or false?

• What conditions do you

think are different between

locations at high and low

elevations? How might

temperature be different?

Why should this affect how

plants grow?

• How many years do leaves

live on trees near your

school?

20

Site Elevation

Characteristic 2,800 meters 3,200 meters

Average shoot length in centimeters (cm) 19.9 20.7

Average needle lifespan (years) 9.5 13.1

Average annual shoot growth (cm)2 2.1 1.4

Average needle biomass per shoot (grams) 4.6 5.9

Table 1. Effect of elevation on shoot characteristics of lodgepole pine.

Figure 1. Measurements taken

on each pine shoot.
Implications

The scientist concluded that

the lifespan of needles in

lodgepole pine can vary, and

may interact with the yearly

growth of the shoot to produce the same amount of

green area regardless of elevation. This may represent an

adaptation of lodgepole pine,

enabling it to live in a wide

variety of environments.

Reflection

• Can you

think of other

examples of

adaptations in

nature? 

From: Schoettle, Anna W. (1990). The

interaction between leaf longevity and

shoot growth and foliar biomass per

shoot in Pinus contorta at two elevations.

Tree Physiology, 7, 209–214.

Discovery

FACTivity

Bring in a

cactus, a fern,

and a plant that

is native to your

local environment. The cactus

has adapted to a hot, dry,

sunny environment. The fern

has adapted to a shady, warm,

wet environment. What kind

of environment does your

local plant live in? Carefully

observe each of the plants.

Compare them. How thick

are each of the stems? Do the

stems look different from one

another? How are the leaves

similar or different? Do the

plants feel different to the

touch? (Be careful with the

cactus!) With the help of your

teacher, explore how each

plant has adapted to its native

environment.

Another

FACTivity!

Using their

numeric results,

scientists often

present their

findings as charts or graphs.

Using the data from Table 1,

you will create your own bar

charts. With the help of your

teacher, complete the bar

charts below. Turn to page 16

to see an example of a bar

chart.

The charts you have created

present the same data as Table

1. Which kind of presentation

do you prefer? Why? What

are the advantages of using

charts instead of tables to present data? What are the disadvantages?

For more information, see:

www.xmission.com/~rmrs/

staffs/labs/laramie/

lar_rm4352.html

21

Average Shoot Length 

in Centimeters (cm)

cm

25

20

15

10

5

2,800 Meters 3,200 Meters

Average Needle 

Lifespan (Years)

Years

15

10

5

2,800 Meters 3,200 Meters

Average Annual 

Shoot Growth (cm)2

cm

2.5

2.0

1.5

1.0

.5

2,800 Meters 3,200 Meters

Average Needle Biomass

Per Shoot (Grams)

Grams

6

5

4

3

2

1

2,800 Meters 3,200 Meters
Meet Dr. Christina Hargis:

“I like being a scientist

because I get to find out new

things about the world that

nobody else has discovered.

Usually the things I discover

are very small facts, but often

they turn out to be important

pieces of information. I hope

that the discoveries I have

made about martens and

other animals will help us do

a better job of keeping

wildlife from going extinct.”

Thinking About

Science...

Scientists

often study animals in their

natural habitat.

When they do this, they try

not to disturb or harm the

animals. Sometimes, they can

study animals from far away

using photography or other

forms of observation. Often,

however, they need to take

measurements of individual

animals to understand

whether they are healthy or

sick, and sometimes just to

identify them. Scientists use

live-traps to capture animals

without harming them. Then,

they can examine the animal

up close before returning him

or her unharmed to the environment. Scientists have 

ethical standards so that they

do not harm the individuals

they want to study. The scientists in this study wanted to

learn about a weasel-like animal called the marten. They

used live-traps to study the

martens before returning

them to their environment.

Dr. Christina Hargis holding

a baby marten.

There Goes the 

Neighborhood:

The Disruption of American Marten Habitat

22
Reflection 

• Why is 

it important to

know whether

marten 

populations are

shrinking?

• How do you think the 

scientists found out about

the marten population?

Glossary:

associated: (e sô'shê â'ted)

closely related or connected

carnivorous: (kär niv'er es)

characterized by feeding on

animals

carrion: (kar'ê en)

dead and putrefying flesh

ethical: (eth'i kel)

relating to what is good 

and bad; moral obligation

extinct: (ik stingkt')

no longer existing

forest manager: (for'ist 

man'i jer) a person who

takes specific actions to

protect and to use natural

resources in a forest

forested: (fôr'is ted)

an area characterized by

dense growth of trees and

underbrush

fragmentation: 

(frag’men tâ’shen) to 

break apart and detach

habitat: (hab'i tat')

the place where a plant or

animal naturally lives and

grows

harvest: (här'vist)

to gather or take a crop 

live-trap: (lîv trap)

a trap that captures an

animal alive and unharmed

population: (pop'ye lâ'shen)

the total of individuals

occupying an area

population density: 

(pop'ye lâ'shen den'si tê) 

the compactness or 

crowdedness of a population

scarce: (skârs)

not plentiful or abundant Figure 1. Different levels of

forest fragmentation.

2% Unforested

21% Unforested

42% Unforested

Thinking 

About the

Environment...

The

American

marten is a 

carnivorous mammal that

lives in forests throughout

Alaska, Canada, and the

Northern United States.

Martens are related to minks,

and just like minks, they have

slinky bodies and soft, rich

fur. They eat mostly mice and

squirrels, but sometimes they

eat berries and carrion. They

hunt for small animals by

slipping quietly around big

logs and tree trunks in forests.

Martens avoid places that do

not have trees because it is

difficult for them to hunt in

open areas. 

Introduction

In many places where

martens live, trees are 

harvested for wood products,

leaving martens with an environment very different from

the forested one they prefer.

When tree harvesting occurs,

the marten’s habitat is broken

up, large patches of open land

are created, and the forest

environment remains only in

little patches, or fragments.

What happens to martens if

they keep finding more open

areas every time they go

hunting for food? Dr. Hargis

and Dr. John Bissonette, the

scientists in this study, wanted to know if marten populations are shrinking because of 

forest fragmentation.

23
Methods

The scientists selected 

18 separate sites—each about

3.5 square miles (9 km2

) in

size—in the Uinta Mountains

of northern Utah so that

many levels of forest fragmentation could be studied. The

sites ranged from 2 percent to

42 percent unforested land

(Figure 1). Some of the sites

were almost completely

forested, while others were

only about half forested.

These sites were like a patchwork of open and forested

land. 

The scientists set 25 livetraps in each of the 18 areas

and checked them for 6 nights

in a row. If a marten was captured in a trap, he or she was

tagged, examined, and

released back into the environment. The scientists

recorded each marten’s

weight, sex, estimated age,

and whether the marten was a

reproducing female. The scientists counted the number of

individual martens captured

in the 25 live-traps placed in

each of the 18 areas over the 

6 days. (How many total

opportunities to capture

martens did they create?) The

number of martens identified

in each area was used as a

measure of the population

density of martens within that

area. Then, the scientists compared the population density

of martens in each area to

determine whether higher levels of forest fragmentation

were associated with lower

marten population density.

The scientists also used livetraps to capture, count, and

estimate the number of smaller mammals on each site.

They did this to understand

whether the martens’ food

supply on each site was plentiful or scarce. 

Reflection

• Why do you

think the scientists tagged the

martens? 

• Why do you think the scientists recorded the martens’

weight, sex, age, and reproductive status?

• Think about the reasons the

marten population might

decline, remain stable, or

increase. Why did the scientists want to know if the

martens’ food supply was

plentiful or scarce?

Findings

The scientists found that on

the more fragmented forest

sites, fewer martens were captured. In fact, the scientists

only captured one marten on

any site that was more than

25 percent unforested 

(Figure 2). The scientists also

found that the martens’ food

supply was plentiful. Dr.

Hargis and Dr. Bissonette

concluded that forest fragmentation has a negative

effect on marten population

density, even when the

martens’ food 

supply is abundant.

24

0 10 20 30 40 50

Percent of Area Unforested

Martens Captured Per 100 Trapsites4

3

2

1

0

Figure 2. Each point (marten) on the graph represents one of

the 18 sites studied. The scientists only captured one marten

on any site that was more than 25 percent deforested. 

No martens were captured at five of the sites.
Reflection

• If the

martens’ food

supply had not

been plentiful,

what conclusion could the scientists

make about forest fragmentation and the decline of the

marten populations?

• If you were the scientists,

what would you tell forest

managers they can do to

help stop the decline of

marten populations?

Implications

If forest managers want

martens to live in the forests

they manage, they must be

careful to harvest trees so that

no more than 25 percent of

each 30-acre site, or about 

7.5 acres, is harvested. It is

also important not to cut trees

in a patchwork pattern, but to

leave large areas forested so

that martens can live in the

forest. 

Reflection

• What human

activity is

impacting 

the marten 

population?

• What might happen to the

marten population if forest

managers do not heed the

advice of these scientists?

• What might happen to the

populations of rodents, rabbits, birds, fruit, and insects

if the marten population

gets very small?

• Is it important to stop the

decline of the marten population? Why or why not?

From: Hargis, Christina D. and

Bissonette, John (1997). Effects of forest

fragmentation on populations of

American Marten in the intermountain

west, In G. Proulx, H. N. Bryand, and P.

M. Woodard (Eds.). Martens: taxonomy,

ecology, techniques, and management,

Provincial Museum of Alberta,

Edmonton, pp. 437–431.

Discovery

FACTivity

The scientists

in this study

wanted to

know about the

forest habitat of the American

marten. In this FACTivity, we

are going to study different

soil habitats. Get five shoe

boxes and line them with

plastic. Fill the shoe boxes

with soil from five different

areas. These areas can be: 

1) a forest, 

2) a compost pile, 

3) a roadside, 

4) a lawn, and 

5) a garden. 

Make sure that you have

supervision when you are digging up soil from the roadside. And, be sure to get

permission to dig the lawn

soil. Carefully investigate the

different soil samples. Do not

injure any animals as you

study them, and disturb them

as little as possible. What

kind of animals are living in

each of the soil samples? How

many animals are living in

each of the soil samples?

What do you think caused the

numbers and types of animals

to be different in each sample? Which soil sample has

been altered the most by

humans? Which one has been

altered the least by humans?

Are some human activities

helpful to animals? Which

ones?

Be sure to return the animals and the soil to their original environment!

25
Meet Dr. Ken Cordell:

“I like being a scientist

because my job is interesting

and because people use the

results of my work in planning

for the future. As an added

bonus, the pay is good which

rewards me for the years I put

into college studies.”

Thinking About

Science...

Scientists can

study all kinds

of topics and

still be interested

in the natural environment.

This study focused on people

and is a type of science called

social science. Social science is

concerned with the feelings and

behavior of people. To find out

about people’s behavior, social

scientists can observe them or

ask them questions. In this

study, the scientist asked a lot

of people a series of questions

about what they do out of

doors in their free time. 

26

Slip Sliding Away

Who Goes Skiing and Snowboarding in America?

Dr. Ken Cordell
ple will go skiing, for example, they can be better prepared to provide the things

people need to go skiing.

Every 10 years, the USDA

Forest Service studies lots of

outdoor recreation activities,

and reports whether the number of people doing each of

those activities is rising or

falling. Dr. Cordell, the scientist in this study, wanted to

know how many people

across the United States went

downhill skiing and snowboarding in the previous year.

Reflection

• What do people need to

have to go downhill skiing?

(Hint—They need more

than equipment, like skis

and warm jackets. They

also need snow, a warm ski

lodge, and someone to

operate the ski lift.) 

• What might happen if agencies and companies did not

know how many people

might want to go skiing?

• If you were the scientist,

how would you find out

how many people went 

skiing or snowboarding 

last year?

Methods

Dr. Cordell used a 

questionnaire to find out how

many people went skiing and

snowboarding in the last year.

Because he could not ask

everyone in the United States

his questions, he had to use a

sample of people across the

country. So that his sample

Glossary:

average: (av'er ij)

the arithmetic mean;

about midway between 

all of the values

bias: (bî'es)

a personal judgment that

might introduce error 

into a research project

demographic: 

(dê'me graf'ik) portraying

the general characteristics

of a population of people

economy: 

(i kon'e mê) a system 

relating to the production,

distribution, and consumption of goods and

services

estimate: 

(es'te mât') to determine

approximately the size or

extent of something

income: 

(in'kum) the amount of

money a person makes

natural resource: 

(nach'er el rê'sôrs) goods

occurring in nature that

are used by humans

outdoor recreation: 

(out'dôr rek'rê â'shen)

activities done out of

doors for fun

questionnaire: 

(kwes'che nâr) a set of

questions used to obtain

information from people

sample: (sam'pêl)

a representative part 

of a larger whole

trend: (trend) a numeric

representation of a change

in quantity over time

Thinking 

About the

Environment...

What do you

need to have to

go downhill

skiing? Well, of course—you

need mountains and you need

snow! Not every place has

these two natural resources.

Places that have mountains

and snow attract visitors who

spend a lot of money doing

things like skiing. This can

help the local economy of an

area by providing jobs that

support activities like skiing.

Skiing and other outdoor

activities depend upon a

healthy and beautiful environment. It is important to realize that the environment can

help the economy, but that it

must also be cared for. If we

take care of our environment,

it can continue to provide

resources for human use and

enjoyment into the future.

Introduction

Do you know anyone who

has gone snow skiing or snowboarding in the past year?

Chances are that you do. It

might even be you! Over the

past 30 years, outdoor activities like skiing have been

growing in popularity, with

more and more people going

outdoors to have fun. Public

agencies, like the USDA Forest

Service, and private companies, such as ski resorts, need

to know how many people do

activities like skiing, and how

many more might like to do

these activities in the future. If

they estimate that more peo27
would not be biased, a computer generated a list of numbers that were used as

telephone numbers. Dr.

Cordell telephoned people in

every State in the United States

and asked them questions

about whether or not they

went downhill skiing or snowboarding. If they had done

either activity, he asked them

how many times they had

gone in the past year. To know

more about them as people, he

asked for demographic information, such as their sex, age,

occupation, and income.

Reflection:

• Why should a

social scientist

guard against

being biased

when choosing

the people to

ask questions of? What

would happen to the results

if the research were biased?

• Why do you think the scientist wanted to know the

demographics of people

who went skiing or snowboarding? 

Results

The scientist found that 8.4

percent of Americans over age

16, or 16.8 million people,

went downhill skiing in the

previous year. He also found

that 2.3 percent of Americans,

or 4.5 million people, went

snowboarding. On the 

average, skiers went skiing 

7.5 days a year. If you add up

all the days that Americans

went skiing, you get 126.5

million days! Dr. Cordell discovered that 74 percent of all

skiers really love to go skiing.

These people also ski often.

The other 26 percent of skiers

do not go skiing very often.

The people who love to go 

skiing and snowboarding the

most are under age 50.

The scientist was also interested in skiing trends. He

compared the number of people who went skiing in the last

year with the number reported in a similar study conducted 10 years ago. Dr. Cordell

estimated that downhill skiing

had increased in popularity

by 58 percent. 10 years ago,

few people knew about snowboarding, so the scientist was

not able to calculate a trend

for it (Figure 1). The scientist

discovered that most skiers

are white males, although

white women ski more than

people of color. He also found

that as incomes rose, people

were more likely to go skiing.

Reflection

• Do you think

that 8.4 percent

of the people in

your community

go skiing? Why

or why not?

• Do you think that 8.4 percent of the people in Texas

go skiing?

• What does that tell you

about the value of averages?

• When will the scientist be

able to calculate a trend for

snowboarding?

Implications

Downhill skiing is a very

popular outdoor recreation

activity. Agencies like the

USDA Forest Service and

companies that own ski

resorts or manufacture ski

equipment should plan for a

continued increase in skiing in

the future. Snowboarding,

28

30

25

20

15

10

5

0

1960 1965 1983 1994

Snowboarders

Downhill

Skiiers

Millions of People

Figure 1. Growth of downhill skiing and snowboarding.
which now only has a small

number of participants, will

also be an important part of

the downhill skiing business

in the future.

Reflection

• Why do you

think that more

and more people are going

skiing?

• What are some other ways

to find out how many people go skiing?

From: Cordell, H. K. (1999). Outdoor

recreation in American life: A national

assessment of demand and supply trends.

Sagamore Publishing.

Discovery

FACTivity

The scientist

in this study

used a questionnaire to discover information. But, because

he could not ask everyone in

the United States his questions, he selected a sample. If

the sample is not biased, it

should represent the whole

population. In this FACTivity,

we are going to discover

whether a sample of your class

can represent the whole class.

First, identify a sample of

students in your class. You

don’t want to be biased, so all

students must have the same

chance of being selected. You

can do this by writing the

name of each student on a

piece of paper. Put all the

names into a hat or bowl and

mix them up. You will select a

sample that is 50 percent of

the class size. Calculate how

many names you will pull

from the hat by taking the

total number of students and

multiplying it by .50.

Before you pull the names,

however, we’ll need to get

some answers from everyone

in your class! Have everyone

take a sheet of paper and

write their name on it. Then,

they should write the answers

to the following questions on

the page:

1.Are you a boy or a girl?

2.Did you ride your bicycle

in the last year?

3.Did you play soccer 

in the last year?

With the help of your

teacher, count the number of

responses to each question.

Then, calculate the percentage

that each represents. For example, pretend your total class

size is 24 and there are 14 girls

in the class. If you divide 14 by

24 you get .58 or 58 percent of

your class are girls. If 20 people

in your class rode their bicycle

in the last year, you will divide

20 by 24 to get .83. That

means 83 percent of you rode

your bicycle in the last year. 

Next, pull names from the

hat or bowl. Now you will calculate the responses to each

question, but this time you

will only use the responses of

the students whose names

were pulled. For each response

to the three questions, calculate the percentage. You will

not divide the responses by the

total class size, but by a number half of the class size. Then,

compare the percentages calculated for each question in

the sample with the percentages calculated for the whole

class. Are they similar? You

should not expect them to be

exact. If they are not similar,

try again by putting all the

names back into the hat and

pulling another 50 percent

sample. If you continue to pull

50 percent samples, most of

the sample responses will be 

similar to the class as a whole.

When scientists use samples,

they know they will not be

exact. However, they feel 

that their findings are close

enough to give them information about the whole

population. 

For more information see:

www.srs.fs.fed.us/recreation

29

Skiing is a popluar sport.
Are Mountain

Stream Channels

Shaped by Flood

and Drought?

Meet Dr. Sandra Ryan

“I like being a scientist

because I like to solve 

problems.”

Thinking About

Science...

When scientists develop

plans to do

research, those

plans influence and limit what

they will discover. If a scientist decides to measure something, that is all he or she can

report about. For example,

the scientist in this study

wanted to know whether

streams changed from their

normal shape when water

was diverted from them and

into another channel. To find

this out, she measured the

width of the streams’ channels. After the research was

done, she reported that she

should have also measured

the channels’ depth and the

size of the stones in the channels. Because she did not measure those things, she could

only report on changes in the

channels’ width. A scientific

study does not always provide

the complete answer to a

question. It often raises other

questions that can be

addressed in future research.

Thinking 

About the

Environment...

When

humans make

changes in the

environment, they are not

always sure what impact

those changes will have on the

environment. In this study,

the scientist wanted to know

if steep mountain stream

channels are changed by

diverting water from them. 

In the Western United States,

water is often scarce where

people live. To provide water

for people living in cities

where water is scarce, it is

diverted from mountain

streams. It is piped through

tunnels across the mountains

to reservoirs for storage and

human use. When this is

done, the existing mountain

streams have a reduced flow,

and sometimes may even 

be dry. 

Introduction

When humans divert water

from mountain streams, there

is less water in the streams at

certain times. The scientist in

this study wanted to know

whether stream channels are

changed as a result of having

30

Go With the Flow!

Dr. Sandra Ryan
Methods

The scientist collected

information from two main

sources to answer her question. First, she identified

which streams she wanted to

study. She wanted to compare

the channels of free-flowing

streams with similar stream

channels that had been diverted. Dr. Ryan and her colleagues then went to the

stream channels and took

measurements in person

(Figure 1). She identified the

stream channel as free-flowing or diverted. Then, she

measured the width of all of

the channels. Once she knew

the widths of the stream channels, she used existing measurements on water flow in

these streams to identify how

much water was diverted

from these stream channels

over the years. The existing

measurements had already

been taken by others and

were recorded in a computer. 

Reflection

• Why did the

scientist compare stream

channels that

had most of the

water diverted from them

with free-flowing stream

channel widths?

• What are the advantages 

of using existing measurements to help answer a

research question? What

are the disadvantages?

Glossary:

channel:

(chan'el) the bed of a stream 

or waterway

diversion dam: 

(di vûr'zhen dam) a barrier

used to divert stream water

from its regular channel

divert: 

(di vûrt') to turn aside 

or draw off from a path 

or course

periodically: 

(pêr'ê od'i kel lê) occurring

at regular intervals

reservoir: 

(rez'er vwär) a place where

water is collected and stored

for use

scarce: 

(skârs) not plentiful 

or abundant

Figure 1. Measuring the

stream channel.

less water at certain times,

and normal flow at other

times. Because most earlier

research had been done on

flatter, wider streams, not

much was known about how

channels change when water

is diverted away from steep,

narrow mountain streams.

Melting snow creates most of

the stream flow, and this flow

can be heavy for days or

weeks when snow is melting.

When there is a lot of melting

snow, water overflows the

diversion dam and briefly

flows again down the stream

channel at a normal flow. 

The scientist wanted to know

what happens to the channel

when water is diverted out 

of it. Does vegetation begin 

to grow along the banks of

the channels? What happens

when water fills the stream

channel again, during periods

of high snow melt or rainfall?

These are the questions Dr.

Ryan, the scientist in this

study, wanted to answer.

Reflection

• What human

needs are being

met by diverting water from

a stream channel and into a reservoir?

Can you think of 10 ways

that humans use water?

• What kind of changes do

you think occur in a stream

channel if the water is

diverted out of it?

31
Results

Dr. Ryan estimated that the

diverted stream channels had

been reduced in water flow

from between 19 percent to 60

percent (Figure 2). This reduction was considered significant. This means that, when

comparing diverted-flow

streams to free-flowing

streams, the difference is

greater than what might have

occurred simply by chance.

She also found that during

years with little snowfall, the

diverted streams almost went

dry. In years with high snowfall, less water is diverted. In

those years, the diverted

stream channels were allowed

to flow as they would have

flowed without being diverted.

During dry years, vegetation often begins to grow

along diverted stream channels, changing the channels’

shape. However, during periods of high water, the water’s

“normal” flow erases many

of these changes. Dr. Ryan

concluded that changes in

these diverted stream channels can hardly be noticed.

Even though the changes can

hardly be noticed, Dr. Ryan is

cautious about concluding

that diverting water out of

mountain stream channels

does not cause changes in the

channels. She noted three reasons for being cautious: 1) If

there are many years in a row

without a lot of snowfall,

more changes might be

observed; 2) The channel surfaces of mountain streams are

very stable, and the changes

might be occurring more

slowly than she could measure with the information

available; and 3) Changes in

mountain channels might be

more detectable if something

other than the width were

measured. Dr. Ryan suggested

that a description of the channel bed, and the depth of the

stones in the channel, might

be a better indication of

change.

Reflection

• What is the

danger of concluding that

diverted stream

channels are

not changed by diverting

water out of them? 

• What other kinds of

changes might be occurring

in and around the diverted

stream channels? (Hint—

Think about the animals

that depend on water for

survival.)

Implications

Because people will continue to live in cities that are

located in dry climates, we

will continue to divert water

from streams and into reservoirs. To make sure that

mountain stream channels are

not changed by diverting

water from them, managers

should allow water to flow

normally in them

periodically. In addition, 

further study is needed to

determine the impacts of

water diversion on waterdependent species, such as

fish and frogs.

Reflection

• What might

happen to fish

and frogs in

years where

there is little

snowfall?

32

0 10 20 30 40 50 60 70 80 90 100

Percent

Minimum Reduction in Flow

Maximum Reduction in Flow

Figure 2. Maximum and minimum flow.
• How would you study the

impact of water diversion

on fish?

• Can you think of any other

actions humans can take to

reduce the impact of stream

diversion on animal

species?

From: Ryan, Sandra (1997). 

Morphologic response of subalpine

streams to transbasin flow diversion.

Journal of the American Water Resources

Association, 33(4), 839–854.

Discovery FACTivity

Streams and rivers get their

water from rainfall and melting snow. Water flows downhill because of gravity, and

eventually flows into the

oceans. Vegetation near

streams and rivers helps to

hold soil in place, keeping it

from being carried by rainfall

and melting snow into

streams and rivers. When 

vegetation near streams and

rivers is disturbed or

removed, it can no longer

hold the soil in place. When

this happens, soil may flow

into streams and rivers. What

activities might cause vegetation to be disturbed near

streams and rivers?

Line an 18"x24" cardboard

box with plastic. Place an

oblong bowl, such as an aluminum foil roasting pan, at

one end. Fill around the bowl

with soil, and build up the soil

in the rest of the box. Shape

the soil so that you are creating a hill. The top of the hill is

at one end of the box, and the

bottom is at the other end,

where the bowl is. Create a

small channel, like a stream,

from the top of the hill down

to the bowl. It can have

curves, just like a stream. The

channel should be lower than

the surrounding soil, and the

soil should gently slope

toward the channel. Get pebbles and small rocks and place

them in the channel. See

Figure 3. The channel represents a stream, and the bowl

represents a pond. Now, get a

watering can with a sprinkler

head (the kind with small

holes in it). Using the watering can, water the soil at the

top of the hill. When you

water, you are simulating

rainfall. Be sure not to water

more than the pond can hold!

Observe what happens to

the soil as the water falls.

Does it stay in place? If not,

where does it go? When

human activities and natural

events cause vegetation to be

disturbed near streams and

rivers, what do you think

happens to the soil? Do you

think this is good for the land

and streams or rivers? Why or

why not?

For more information, see:

www.xmission.com/~rmrs/

staffs/labs/laramie/

lar_rm4352.html

33

Figure 3. Setup for FACTivity.
Please photocopy this form for each article

you read and complete these evaluation

forms. Send them to the address below.

1.The article I read was:

■ Quit Yer Horsin’ Around

■ Slip Sliding Away

■ Finding Ways to Soak Up the Rays

■ Quaking in Their Roots

■ Are We Having Fungi Yet?

■ There Goes the Neighborhood

■ Go With the Flow

Circle or check the answer that best describes

how you feel about the article you just read.

2.The article was:

■ Very easy to understand

■ Easy to understand

■ Hard to understand

■ Very hard to understand

3.The article was:

■ Very interesting to read

■ Interesting to read

■ Somewhat interesting to read

■ Not interesting to read

4.Did you learn something from reading the

article? ■ Yes ■ No

5.Did you try to answer the Reflection

Questions? ■ Yes ■ No ■ Some of them

If you read and tried to answer the Reflection

Questions, did they help you to think about

the article? ■ Yes ■ No

6.Would you like to read another article?

■ Yes ■ No

7.How old are you? (Circle)

10 11 12 13 other age: _____

8.What grade are you in? (Circle)

4th 5th 6th 7th 

9.Are you a girl or a boy?

■ Girl ■ Boy

Now write in your answer:

10.What did you learn from reading 

the article?

11.What is your favorite subject in school?

Please send to:

Dr. Barbara McDonald

USDA Forest Service

320 Green St.

Athens, GA 30602-2044

Thank you!

34

Students—Tell Us What You Think About The Natural Inquirer
Please photocopy this form for each article

you read and send the completed evaluation

forms to the address below.

For each article that you read, please answer

the following:

Name of Article:________________________ 

1.Would this article help you meet any of

the required statewide science curriculum

standards? ■ Yes ■ No

2.How close to the appropriate reading and

comprehension level for your students is this

article written?

■ Very close

■ Somewhat close

■ Not close

3.If the article is somewhat close or not close

to the appropriate reading and comprehension

level, is it:

■ Too hard

■ Too easy

4.Will you use this article in your classroom

as an educational resource?

■ Yes ■ No ■ Why or why not? 

5.Please rate the article sections on a scale of 

1 to 5. One means the section was not useful

at all, five means the section was very useful.

Not Very

useful useful

Meet the Scientist 1 2 3 4 5

Glossary 1 2 3 4 5

Discovery FACTivity 1 2 3 4 5

Thinking About Science 1 2 3 4 5

Thinking About 

the Environment 1 2 3 4 5

Introduction 1 2 3 4 5

Methods 1 2 3 4 5

Results 1 2 3 4 5

Graphs, figures, photos 1 2 3 4 5

Implications 1 2 3 4 5

Reflection Sections 1 2 3 4 5

6.Was the “Project 2061/National Science

Curriculum” matrix useful to you?

■ Yes ■ No ■ Somewhat

7.Was the “Note to the Teacher” useful 

to you?

■ Yes ■ No ■ Somewhat

8.What grade(s) do you teach? ______

9.What subject(s) do you teach?

10. What is your zip code? __________

35

More on page 36 ☞

Teachers—Tell Us What You Think About The Natural Inquirer
11. For any of the sections you rated with

either a “one” or a “two” in question 5,

please indicate why the section was not useful

or how it can be improved:

Meet the Scientist

Glossary

Discovery FACTivity

Thinking About Science

Thinking About the Environment

Introduction

Methods

Results

Graphs, figures, photos

Implications

Reflection Questions

12. Other comments or suggestions:

Please send to:

Dr. Barbara McDonald

USDA Forest Service 

320 Green St. 

Athens, GA 30602-2044

Thank you!

36
C

Which National Standards* Can Be Met by The Natural Inquirer?

*From Project 2061—American Association for the Advancement of Science Articles

Standards

Scientific Enterprise X X X X X X

Scientific Inquiry X X X X X

Processes That Shape the Earth X X X X

Communication Skills X X X X X X

Critical Response Skills X X X X X

Reasoning X

Interdependence of Life X X

Technology and Science X X

Issues in Technology X X X X X

Political and Economic Systems X

Uncertainty/Computation

& Estimation X

Social Tradeoffs X X

Constancy and Change X X

Cultural Effects on Behavior X

Shapes X

Regulation and Behavior X

Symbolic Relations X

Science Values and Attitudes X

Diversity of Life X

Mathematics, Science

& Technology X X

Heredity X

The Nature of Mathematics X

Values and Attitudes X

Mathematical Inquiry X

Systems X X X

Additional Standards Met

(From the National

Science Foundation)

Natural Hazards X X X

Populations and Ecosystems X

Reproduction and Heredity X

Diversity & Adaptation 

of Organisms X Quit Yer Horsin’ Around! Slip Sliding Away Finding Ways to Soak Up the Rays Quaking in Their Roots Are We Having Fungi Yet? There Goes the Neighborhood!

Go With the Flow
The Forest Service is part of

the Federal Government. It is

made up of thousands of people who care for the Nation’s

forest land. The Forest Service

manages over 150 national

forests and almost 20 national

grasslands. National forests

are similar in some ways to

national parks, except that

unlike national parks, national forests are used for many

purposes. These purposes

include providing clean water;

places for wildlife and fish;

places for people to hike,

camp, and do other outdoor

activities; healthy soil; trees

for lumber; and minerals.

Some people in the Forest

Service are natural resource

scientists, whose research is

presented in this journal.

Forest Service scientists work

to solve problems and provide

new information about natural resources so that we can

make sure our environment is

healthy, now and into the

future.

The U.S. Department of

Agriculture (USDA) prohibits

discrimination in all its programs

and activities on the basis of race,

color, national origin, gender,

religion, age, disability, political

beliefs, sexual orientation and

marital or family status. (Not all 

prohibited bases apply to all

programs.) Persons with disabilities who require alternative

means for communication of

program information (Braille,

large print, audiotape, etc.) 

should contact the USDA’s

TARGET Center at 202-720-2600

(voice and TDD). 

To file a complaint of

discrimination, write the USDA

Director, Office of Civil Rights,

Room 326-W, Whitten Building,

14th and Independence Avenue,

SW, Washington, DC 20250-9410

or call 202-720-5964 (voice or

TDD). USDA is an equal 

opportunity provider and

employer.

What is the Forest Service?

Visit these websites for more information:

USDA Forest Service: 

www.fs.fed.us

The Natural Inquirer: 

www.fs.fed.us/research/natural_inquirer.htm

Conservation Education: 

www.fs.fed.us/outdoors/nrce/

Rocky Mountain Research Station: 

www.xmission.com/~rmrs/

NatureWatch: 

www.fs.fed.us/outdoors/naturewatch/default.htm

Woodsy Owl: 

www.fs.fed.us/spf/woodsy

Smokey Bear: 

www.smokeybear.com

National Forest Information: 

www.fs.fed.us/links/forests.shtml

National Forest Recreation: 

www.fs.fed.us/recreation/recreation.shtml

United States Department of Agriculture

Forest Service